1. Field of the Invention
The present invention relates to photographic apparatus and more particularly to an improved cocking mechanism for moving a piezoelectric firing spring to a latched position in such apparatus.
2. Description of the Prior Art
The use of a piezoelectric crystal to power a flash unit in photographic apparatus is known. See U.S. Pat. Nos. 2,856,564; 2,972,937 and 3,106,080. Recently apparatus has been developed in which a plurality of flashlamps, each fireable by means of an electric pulse generated by a piezoelectric crystal, are assembled in a multi-lamp array. In one such array, as disclosed in more detail in U.S. Pat. No. 3,941,447, all of the lamps are aligned in the same direction and each lamp has its own reflector. A switching mechanism is provided, internal to the array, for properly sequencing firing of the individual lamps. In photographic apparatus adapted to use such an array, a piezoelectric crystal striking mechanism is provided, including a firing spring with an associated hammer, movable from a latched position to strike the piezoelectric crystal and thereby generate an electric pulse. In addition, a cocking mechanism is provided for moving the firing spring to its latched position prior to a subsequent actuation. In cameras of the type having a film advance slide in close proximity to the piezo firing spring, one method of cocking the spring is by means of a ramp associated with the film advance slide. See U.S. Pat. No. 3,958,259 wherein this simple but effective method of cocking the piezoelectric firing spring is described. However, in cameras in which the firing spring is not located in proximity to the film advance mechanism, this method of cocking the firing spring is not practical and some other method must be sought. Such a camera is described in the above-referenced, co-pending U.S. patent applications wherein the piezoelectric firing spring is cocked by means of pivotal linkage cooperating with the body release member upon return of the body release member from its actuating position. An extended portion of a high energy lever that operates an impact shutter serves as the latch for the piezoelectric hammer. The present invention is directed to an improvement in such apparatus.